In the Nachi exam the answer for lifespan of asphalt roofing is 15-25 years. I work on Vancouver Island & here 8-15 years would be our norm. Fiberglass laminates perform much better here- 15+. Are the results similar in the rest of canada?

Stephen, here in Medicine Hat, Alberta, those stats of 15-25 years is bang on, depending on quality/rating of asphalt shingles. Our climate is like desert out here, hot and dry.

Doesn’t lifespan depend on pitch of roof, colour of shingles, ventilation, quality of shingles, quality of workmanship, exposure? Hmmmmm.

all of the above, but first and foremost shingle weight

I’m sure the NACHI exam is looking for the statistical average of a typical, properly installed asphalt shingle roof. Of course it matters on improper installment, ventilation, slope, etc. etc. thats a no brainer. The word lifespan is made up from an average of typical installments, not just one or two poor/incorrect installations.

Your area/climate is bound to be much tougher on shingles with the amount of moisture/rainfall you have. In our area, there is things like hail storms that can dramatically shorten the AVERAGE LIFESPAN by pitting and abnormal granule loss, which is designed to protect the felt and asphalt coating from the harsh elements…thus extending and preserving the life of the shingle. The typical shingle used here is a 20 year type/weight, with many of the higher end homes switching to an architectural, heavier 30 year type for appearance and durability.

So to answer your question…in out area it is TYPICALLY a 15-25 year lifespan. That is the normal expectancy around here.

I believe Raymond hit it on the nose here.

Interesting Article:


Thanks Marcel! Good find!

Ventilation and maintenance are the big 2 items.
20-25 years and you are pushing for a re-roof.
Then again, just how many home owners really
take care of their roofs properly?